Cancer is a class of diseases or disorders characterized by uncontrolled division of cells and the ability of these cells to invade other tissues, either by direct growth into adjacent tissue through invasion or by implantation into distant sites by metastasis. Metastasis is defined as the stage in which cancer cells are transported through the bloodstream or lymphatic system. Cancer may affect people at all ages, but risk tends to increase with age, due to the fact that DNA damage becomes more apparent in aging DNA. According to the American Cancer Society, well over one million new cases of cancer are diagnosed each year in the United States. Cancer causes over a half million deaths each year in the United States, making it the second leading cause of death.
Many different molecules are thought to play a role in the complex pathogenesis of cancer. The mitochondrial protein cytochrome c (Cyt c) is one such molecule and is believed to be important in the suppression of cancer development because of its role as an important initiator/amplifier of programmed cell death or apoptosis. Specifically, following its translocation to the cytoplasm, Cyt c binds Apaf-1 and serves as a cofactor in caspase-9 activation (Liu et al., Cell, 1996; 86: 147-157). Cyt c has considerable clinical potential as a serum marker for aberrant apoptosis. In several clinical trials, an increase in serum Cyt c has been observed in a variety of patients including those with cancer, myocardial infarcts, apoptosis-associated liver disease, systemic inflammatory response syndrome, and influenza virus-induced encephalopathy (reviewed by Jemmerson et al., Antiox. Redox Signal., 2005; 7: 1158-1172).
For at least these reasons, a need exists for sensitive methods of detecting Cyt c in samples and antibodies for implementing the same. A need also exists for methods of detecting molecules that interact with Cyt c.